Torkamani Amir Ehsan, Juliano Pablo, Ajlouni Said, Singh Tanoj Kumar
CSIRO Division of Animal, Food and Health Sciences, 671 Sneydes Road, Werribee, VIC 3030, Australia; Department of Agriculture and Food Systems, Melbourne School of Land and Environment, The University of Melbourne, Parkville, VIC 3010, Australia.
CSIRO Division of Animal, Food and Health Sciences, 671 Sneydes Road, Werribee, VIC 3030, Australia.
Ultrason Sonochem. 2014 May;21(3):951-7. doi: 10.1016/j.ultsonch.2013.11.021. Epub 2013 Dec 8.
Ultrasound (US) has been suggested for many whey processing applications. This study examined the effects of ultrasound treatment on the oxidation of lipids in Cheddar cheese whey. Freshly pasteurized whey (0.86 L) was ultrasonicated in a contained environment at the same range of frequencies and energies for 10 and 30 min at 37°C. The US reactor used was characterized by measuring the generation of free radicals in deionized water at different frequencies (20-2000 kHz) and specific energies (8.0-390 kJ/kg). Polar lipid (PL), free and bound fatty acids and lipid oxidation derived compounds were identified and quantified before and after US processing using high performance liquid chromatography equipped with an evaporative light scattering detector (HPLC-ELSD), methylation followed by gas chromatography flame ionized detector (GC-FID) and solid phase micro-extraction gas chromatography mass spectrometry (SPME-GCMS), respectively. The highest concentration of hydroxyl radical formation in the sonicated whey was found between 400 and 1000 kHz. There were no changes in phospholipid composition after US processing at 20, 400, 1000 and 2000 kHz compared to non-sonicated samples. Lipid oxidation volatile compounds were detected in both non-sonicated and sonicated whey. Lipid oxidation was not promoted at any tested frequency or specific energy. Free fatty acid concentration was not affected by US treatment per se. Results revealed that US can be utilized in whey processing applications with no negative impact on whey lipid chemistry.
超声（US）已被推荐用于许多乳清加工应用中。本研究考察了超声处理对切达干酪乳清中脂质氧化的影响。将新鲜巴氏杀菌乳清（0.86升）在密闭环境中于37℃下，在相同频率和能量范围内超声处理10分钟和30分钟。所使用的超声反应器通过测量去离子水中不同频率（20 - 2000千赫）和比能（8.0 - 390千焦/千克）下自由基的产生来表征。分别使用配备蒸发光散射检测器的高效液相色谱（HPLC - ELSD）、甲基化后接气相色谱火焰离子化检测器（GC - FID）以及固相微萃取气相色谱质谱联用仪（SPME - GCMS），在超声处理前后对极性脂质（PL）、游离脂肪酸和结合脂肪酸以及脂质氧化衍生化合物进行鉴定和定量。发现超声处理后的乳清中，在400至1000千赫之间形成的羟基自由基浓度最高。与未超声处理的样品相比，在20、400、1000和2000千赫频率下超声处理后，磷脂组成没有变化。在未超声处理和超声处理的乳清中均检测到脂质氧化挥发性化合物。在任何测试频率或比能下，脂质氧化均未被促进。游离脂肪酸浓度本身不受超声处理的影响。结果表明，超声可用于乳清加工应用中，且对乳清脂质化学没有负面影响。
